Tension control for rolling mills



Jan. 3, 1933. w, Q CORYELL 1,892,934

TENSION CONTROL FOR ROLLING MILLS Filed Jan. 8, 1930 2 Sheets-Sheet lJan. v3, 1933..l w C. CORYELL 1,892,934

TENSION CONTROL FOR ROLLING MILLS Filed Jan. 8, 1930 v2 Sheets-Sheet 2Patented `ian. 3, 1933 Unirse Askreries PATENT erstes WILLIAM o.vCORYELL, or YoUNGsfrowN, OHIO, Assronoa To REPUBLIC STEEL cora-PORATION, or YOUNGsTOwN, OHIO, A CORPORATION or NEW Jnssnv 4'rinvsroivCONTROL son ROLLING MILLS Application led lanuaryr, 1930. Serial No.419,276.

VThe present invention-relates to tension control for rolling millswherein tension'ls applied to the work asfit. is being lacted upon bythe mill and the invention consists in novel 5 apparatus for controllingsuchA tension. The

inventionis in yone sense related to the method of my prior p-atent#1,618,515 filed F ebruary 22,1927, wherein I disclose a way'ofobtaining-great elongations inthe metal worked upon'with a minimum ofannealings.' The present inventionjis especially useful in' carrying outthe method of that patent.

One object of the present invention is lto devise a control ofthe classdescribed which will permit i of accurate and nice regulation. Anotherobject is to produce a control which will be `especially a'jpplicableto-` continuous mills. "i Other `objects-include freadyoperation of 'the'control, economy of'its manufacture and maintenance, *and4 durabilityvand eiicien'cy in service-y .f i

The preferred form of the invention 1ncludes working rolls, means for:applying a p'ull to A'the strip to create" inE the outgoing portionofthel strip a tension which is fairly constant,1retarding the ingoinglend vof the stripby'means'fwhich will drive agenerator which carries anelectric load, and :then adjusting 'the load on the generator to give anaccurate retarding tension in the strip on the ingoing side of therolls.l In this way I have found it possible to obtain great uniformityin tension and thereby to make'it possible to adjust the retardingtension to a point approaching the ultimate rupturing tension/of thestrip. This means that by the novel retarding means I employ -I can geta maximum reta-rding stress. This when cou pled with the forward pull Onthe strip gives components which may be of high value for the forming ofthe resnltants which cause the metal to fiow where the tension rollingof my prior patent is employed.'

Having set forth the character and nature of my invention in thisgeneral way I would now call attention, for a better understanding ofthe same, to the following detailed description taken in connection'withthe accompanying drawings wherein the preferred embodiment of theinvention is fully set forth.

For determination of the scope of the invention attention is directed tothe appended claims.

In said'drawings, Fig. lis a plan view of a continuous mill plantconstructed and arranged in accordance with the present invention, partsof the mill being shown in section taken on a plane indicated by theline l-l of Fig. 4; Fig. 2 is a rear elevation of the same; Fig. 3 is avertical section through one of the mill couplings and gearings, theplane of section being indicated by the line 3 3 of Fig. 1"; Fig. i is aside elevation of the plant arrangement of Fig. l; Fig. 5 is anelevation of gearing through which energy is transmitted to the electricgenerator of the plant, parts being shown in section taken on a planeindicated bythe line--5--5 of Fig. l; Fig. 6 isa diagram ofthe mechanismof Fig. l illustrating the electrical connections; and Fig. 7 is adiagram of a strip mill plant showing additional control rolls and amodified pulling device. Throughout these views like characters refe-rto like parts.

Referring to the drawings in detail, A designates a strip of metalpassing through mills B and C and being wound upon a reel D. The latterserves as a pulling device to place tension in the strip. The retardingorpoWer-consuming mechanism is the electric generator Gr with its loadedcircuit F. The pulling device D is here shown driven b-y an electricmotor M. In the mill plant of Fig. 7 the reel D is replaced by a pullingmachine H of somewhat different construction.

Although the work upon which the mill operates is shown as a metal stripA, it will be understood that the work might consist of metal pieces ofother shapes and kinds. In

such instances the pulling devices D and H tion with metal strip as thematerial worked upon and I have designed the illustrated mechanism forhandling that material.

rIhe mills B and C are similar in construction and consequently thedescription of one will apply to both. Thus, in mill B, and 11 designatethe housings whose feet 12 and 13 rest upon the shoes of 14 and 15extending. transversely of the direction of travel of strip A. Thehousings may be of any desired construction and are provided with theusual Windows 16 in which are located lower boxes 17 and upper boxes 19.Breakers 18 bear upon the upper boxes 19. These. boxes provvide bearingsfor the lower roll 20 and the upper roll 21. In the present Lmill therolls 20 and 21 are backing-up rolls of large diameter for reducingrolls 22 and 23 of small diameter. The latter'are offset-'from thevertical plane through the axes of the rolls 20 and 21. This offset rollconstruction constitutes the subject matter of my application Serial No.309,531, led'October 1, 192,8. The bearings for the reducing'rolls 22and 23 arevprovidedA byboxes 24 `and/25 'carried in any suitable way bythe housings-'10 and 11. Each housingis provided with an adjusting'screw26 which forms the screw-down mechanism of the mill. The lower ends ofthese-screws press upon the breakers 18. Any suitablescrewdoWnmechanism-may be used on these mills. Suitable counterbalances' for the rolls will also be employed, but thesearewell knownand need not be illustrated. Reference may be hadto my prior Patent No.1,233,647, dated Iuly117, 1917-, for anexample.

I .In `the 'ca-se of mill C the shoes 14u and '15 upon which thefeet12and13 restare shorter than the corresponding shoes 14 and 15 Iuponwhich the feet12 and 13 ofmill B rest; The lattermill is the one whichis connected up to the retarding or power-consuming generator G,andconsequently'the same 'shoes are used for supporting the feet 27 and28 of a gearcasing 29 containing the gear Wheels 3() and 31 andintended-for transmission of power from the rolls of mill B to thegeneratorv G. Gear Wheel 30 is keyed to a shaft 32 which is journaledatits ends in suitable ybearings in the Walls of the casing 29. Similarly,gear wheel 31 is keyed to a-shaft 33 which has its ends journaled inbearings in the same walls of the casing and, in the instance shown, inthe same vertical plane as the shaft 32.- The adjacent neck 34 ofroll 21of mill B is coupled to the end of shaft 32 by means of a coupling shaft35 and sliding couplers 36. In the same way the neck 37 of roll 20 ofmill B is coupled to the end of shaft 38 and sliding couplers 39. As ameans of support, the coupling shaft 38 has a central cylindricalportion 40 which bears upon a block 41 carried by a frame member 42, atthe upper end of box 43 resting upon a suitable support.

To extend this supporting force `to the upper coupling shaft 33, Iprovide the latter shaft with a central cylindrical portion 44 whichrests upon a block 45 carried by member 46 resting upon a block 47 whichbears upon the upper portion of the cylindrical bearing surface 40 ofthelow-er coupling shaft 38. The gear wheels 30- and'- 31 mesh with eachother and consequently there is no slippage between the rolls 2O and 21of the mill.

The end of" shaft 33 distant from the mill B is provided with a"coupling'head 48 and .this headlits the head of the coupler 49 and thelatterat its opposite ends lits aA coupling head 50 upon the adjacentend of shaft 51 which carries gear wheel 52 which mesheswith-pinion53.mountedupon shaft'54 inline witlrgeneratorshaft v62.v'Bhe-shafts 51 and 54v are journaled -at their opposite.t ends; inbearings 55 and 56, respectively, formed lin Webs 57 and 58 :of asupporting casting: 59.- The latter is independent of theshoes 14-'and15, but obviously may/be, mounted upon' .any suitable supportE suchl asthe-floor.' 60. upon which the slioes'.14and'15are located. The end'of.the shaft 54 which is distant frcmfthe mill BV is connected'bycouplingf61 to the end of the shaft62 ofthe rotor of the generator G.'The parts of the generator. are-suitably supported' upon a base 63, theshaft 62- having bearings64 and 65 extending upward fr'ornthe .base- Thegenerator struoturefmay be varied a l`great deal 5in form andthere-seemsto be no necessity of describing-any pariicular generator indetail.4'Ifhe base63 may rest upon'. any 4suitable -elevationwof the floor 60which is shown stepped, withportions suited i-n elevationto the.mechanisms installed;

Ilhe reel .D is one devic'ewhich .may belemployed' for giving .tensiontothe strip A. When employed-it must be, of course, positively driven.In the embodiment showngthis isaccomplished.y by an electric motor M andal gear train including pinion 66 and gear wheel'67. The reel Dcomprises a drum 68 mounted uponf'a shaft 69 toI which reel 67 is keyed;The drum-68 'is provided with some means' -for attaching the. end ofthestrip.' Such means are well known and as the same in itself forms nopart ofthe present invention, it seems unnecessary to illustrate anymeans of attachment. Ordinarily, a slit of some kind is provided intowhich the end-of the strip -is inserted. Many such reels.A are on the.market andfavaila'ble to those who would practice the presentinvention. The shaft 69 upon which the drum 68 is lmounted is journaledin suitable bearings 70 and 72. The former is found in the upper portionof a-pedestal 71 mounted upon the floor 60 as Vare the other varioussupports. The latter is similarly found in and supported byv a pcdestal73, also located upon the floor 60. The pedestal 73 also provides abearing 74 for the pinion shaft 75 to-which the pinion 66 is keyed. Abearing 76 is a mate to the bearing 74 but is mounted upon a separatesupport 77 `also adapted'to rest upon the floor 60. The shaft extendssome distance beyond thebearing 74 toward the shaft 78 of the motor M.The shafts :7 5 and 78 are'in alignment and joined by a coupling 79. Mo-

'torshaft 78 finds its support in bearingsSO and-81 mounted respectivelyupon pedestals 82and 83 rising from a base 84:. The latter, as vwith theother pieces of apparatus, rests upon .the floor 60. The motor M, likethe generator G, is lof Well-known construction and need notbe describedin detail. i Thegeneral arrangement of the mill-plant thusv fardescribed is diagrammatically illustrated in Fig. 6. There some ofthe-parts are -omitted for clearness, but the general arrangement will] bereadily understood. The generator G, which forms the retarding mechanismhas its terminals 85 and 86 connected toa loaded circuit F comprisingconductors: 87and 88 which lead respectively from' said terminals 85 and86, the one to the terminals lof. a seriesfof electric lamps 89 and-.theother tothe movable arm 90 of a rheostatR, Theseveral contacts 9110i therheostat are connectedv at intervals to the turns of a resistanceWinding 92. The connections are in series so that asthe arm 90 is movedto the left, as seen in Fig. 6, the resistance in circuit is cut down,and when moved to the right the resistance in circuit is increased. Theleft-hand contact 91 is connected by conductor 93 to the other terminalsof the lamps 89. Thus We have a simple loaded electrical circuit whereinthe lamps 89 are a steady load and the rheostat R provides a variableload.

The motor M which drives the pulling device D has its terminals 94 and95 connected by conductors 96 and 97, respectively, to supply means 98and 99 leading from a suitable source of supply of electricity. Themotor M, like the generator G, may vary considerably in construction.There are many motors and generators at present on the market which Willserve the purpose required by the present invention.

In operation the strip is threaded between the reducing rolls of themills B and C and has its end secured to the drum 68 of the pullingdevice D. The motor M is started and a pull is exerted upon the strip Ain the direction of the arrows. The tension thus applied causes thereducing rolls 22 and 23 of each of the mills B and C to press againstthe strip to apply rolling pressure, and thus reduce the thickness ofthe strip, flatten it, or otherwise treat it according to the positionof the backing-up rolls 20 and 21. The posit-ion of the latter isdetermined by the positions of the screw-down screws 26. In the instanceshown, the mill C is not connected to any driving source but therequired reduction pressure is obtained through the screw-down and theaction of the oiset rolls against the large diameter backing-up rolls inresponse to the pull of the strip. The same is true of the rolls of millB, but in the latter case the rolls are connected to the retardingelectric generator G, and that generator is driven by the rotation ofthe backing-up rolls 20 and 2l. K

As the strip A is advancing, the small diameter rolls 22 and 23 arerotated by the frictional contact or the strip with the rolls, and thenthe small diameter rolls by frictional Contact with the backing-np rollsrotate the latter. The rotation of the backing-up rolls is communicatedto the gearing through the rotor of the generator G. The action of therotor is resisted by the load upon the external circuit includingrheostat R- and lamps 89. lVhen contact 90 is in engagement with theleft-hand contact 91, as the parts are viewed in F ig. 6, there is aconstant load upon the circuit. That load is produced by lamps 89. Thisconstant load will exert some retardation upon the connected gearing androlls, andv consequently there will be exerted by the mill B aretardation upon the advance movement of the strip A. here the motor Mis a constant torque motor, the pull of the pulling device D will not belessened by this retardation caused by the mill B, but the effect Willbe to increase the tension in the strip A over that which is produced bythe pulling device D when acting alone.

It is apparent that the retarding effect produced by the steady load ofthe lamps 89 may have its application to the strip A varied by thescrew-down mechanism of the mill B. Such mechanism might be loosened uplto the point Where the strip A would, through slippage, fail to drivethe generator G. But it should be understood that the screw-downmechanism should be adjusted so that there Will be no slippage betweenthe strip A and the roils 22 and 28 on the one hand, or between therolls and 23 and the rolls 2O and 2l on the other hand. Thus with thesteady load upon the generator circuit, a tension is produced in thestrip A which is the result of tension applied by the pulling device Dand an opposing tension app-lied by the mill B. The constant load may bedetermined Within desired limits by the number of lamps 89 included incircuit. The eii'ect of this is to similarly determine roughly thetension in the strip A. F or refinements in adjustment of the tension inthe strip the rheost-at R will be used. By shifting its arm 90 back andforth over its contacts 91 the load on the generator circuit Will bevaried, and accordingly the resistance offered to the rotor of thegenerator will be varied, and this variation Will be communicated to thegearing through the rolls of mill B. Thus, by a deft handling of therheostat arm 90 it will be possible to obtainsuiiiciently reined tensionadjustments. Workmen withthe apparatus will soon. acquire the ability toobtain nice-results with diferent kinds of work.

Instead 'of employing a reel for thepulling device, I may prefer in someinstallations to .employ a pulling machine such as the machine Hdiagrammatically illustrated in Fig. 7. The use of such a pullingmachine Will allow the strip or other workto passcontinuously through'the plant from one end -to the other. In other Words, the pullingmachine provides for a continuous straightaway operation ofthe materialbeing `acted upon. In this diagram the-*strip firsty passes 'betweenrol-ls L which may` be pinch rolls or the rolls of a small mill. Theseengage the Work and pass it along toward the mill B. After passingthrough thel mills B and C the strip A travels around the drums 100,101, A10:2, and 103 of the pullingmachine H. After leaving the drum 103thefstrip passes between rolls N which arethe last to actA upon thestrip. The pullingr machine .H has-its drums-individually driven, and-these drums act likeuc'apstans to pull upon' the strip by friction'alengagement with it. To insure proper fric-tion', the rolls TN must bepositively driven to exert a slight pull upon the strip leaving the lastJdrum'103 of vthe pulling machine. It is believed that this pullingmachine need not be further described, as a full description andillustration of the same will be found in myprior application, SerialNo. 280,681, {iled May 26, 1928.

In carrying out my invention it will be apparent that certainalterations may: be madein the mechanisms andjarrangements illustratedwithout departing from the spirit and scope of the invention. Thus,thelamps 89 in the circuit F might bevreplaced by other energy consumingdevices. Again,'as indicated, different pulling devices might beemployed to take the place of the reel D and pulling mechanism H.Likewise, different types of mills might be employed. Other changes willalso suggest themselves to per# sons skilled in the art.A I,therefore,ldo not Wish to be limited to the specific mechanisms andarrangements shown, but aim to cover by t-he terms of the claims allsuch alterations and modifications as rightly come within the spirit andscopeof my invention.

IVhat I claim as new and desire to secure by a patent of the UnitedStates is:

1. In a cold rolling strip mill, working rolls for engaging andoperating upon the strip as it passes between them, means coperatingwith said rolls to produce a high substantially constant tension in theoutgoing portion of the strip, means for restraining the ingoing portionof the strip, a loaded elec-v tric generator driven by said restrainingmeans and operative through the latter to exert an even retardingtension in the ingoing applying aihigh .substantially constant -pulflupon the strip. onthe voutgoing side of' said main rolls, auxiliaryrolls for-engagingand retarding the strip on the ingoingsideof 'saidmainrolls, a loaded'electrio generator driven by' energy derived from saidauxiliary rol-ls and-operative through the latter yto exert an'evenretarded tension-'inthe strip yon the .ing'oing side ofsaid mainrolls,'andi-'rmeans for regulating the load on said generator# to nicely"adjust theretarding tension on'the ingoing side vof said main rolls,whereby` the retarded tension `in the strip may' be'rai'sedto, andmaintainedin, proximity to the Iultimate rupturing tension of thestrip.-7V In witness whereof, Ihereuntojsub'scribe my name this L1thdayof Jan., A. D. 1930.

f "'WILLIAM C. CO'RYELL.

